Taxonomic significance of seed sculpture and pollen ecto-mycoflora at the infraspecific level: Brassica tournefortii case study

Several populations of Brassica tournefortii (Brassicaceae) occurring in Egypt are investigated from the micromorphological point of view (seed ornamentations). The species is known to show a notable phenotypic plasticity and five morphotypes was identified in the past. Furthermore, a soil analysis as well as a study of the fungal species from anthers were carried out. The aim of the study is to verify the taxonomic value of the morpholotypes of B. tournefortii and their ecologic relationship with soil variables. The results obtained demonstrated that the five morphological forms can be distinguished based on the seed sculpture. The Canonical Correspondence Analysis (CCA) exhibited a clear correlation between the soil variables and the identified forms. Six species of fungi were detected from the ecto-anthers in the Forms (F2-F4), while F1 was lacking the fungal species. The study revealed that the morphological plasticity of studied B. tournefortii depends on ecological factors.     

Mechanism of rice bran lipase inhibition through fermentation activity of probiotic bacteria

Rice bran oil is known as wonder oil and it is the most important vegetable oil in Asia. Rice bran oil is extracted from bran that is the outer hard layer of rice. It is an emerging category in edible oil with a lot of nutritional properties and health benefits. Rice bran oil is heart-friendly, boosts up immunity, and prevents from other diseases occurring commonly in Pakistan. The current study aimed to stabilize rice bran oil through different probiotic isolates and to assess the nutritional content of rice bran oil after stabilization. The study was aimed to inactivate naturally occurring lipases that can hydrolyze oil into glycerol and free fatty acid which is a serious problem that gives it a rancid taste and smell. Antilipase activity was used to inactivate naturally occurring lipases that are a huge threat to the stabilization process. The fermentation process utilizes antilipase activity without affecting the nutritional value of oil. Lactobacillus strains were used for the stabilization of rice bran oil. Rice bran oil was extracted in the Soxhlet apparatus. The probiotic lab isolates Lactobacillus delbrueckii S2, Lactobacillus casei S5 and Lactobacillus plantarum S13 were applied to it to increase its shelf life and prevent oxidative rancidity. The extraction temperature of rice bran oil was maintained above 40 °C to inhibit lipase activity. Rice bran oil samples were stored at refrigeration temperature to arrest lipase activity. Probiotics maintained acidic pH to keep oil stabilization. Qualitative analysis was done to confirm rice bran oil stabilization. Determination of Free Fatty Acid (FFA) and saponification value confirmed that oxidative rancidity of rice bran oil was controlled by probiotics. FFA count was less than 10% and Saponification Value (SV) was 180. GC analysis was performed to analyze the FFA profile. Gas Chromatography results have shown 3 fatty acids. Statistical analysis has shown non-significant effect on different incubation temperatures of Lactobacillus isolates. Among the biological methods of stabilization, the use of probiotics is a novel concept and recommended for commercial application.     

Effects of different gelling agents on the different stages of rice regeneration in two rice cultivars

Plant tissue culture technology offers a solution for meeting the increasing commercial demand on economically important plants such as rice, a widespread dietary staple. However, significant genotype-specific morphogenetic responses constitute a considerable on rice regeneration in plant biotechnology contexts. Aside from genotype dependency, the components of the nutrient media including gelling agents have an important impact on regeneration efficiency. The current study explores the effect of different gelling agents on various stages of rice regeneration in two Egyptian rice cultivars-Sakha104 and Giza178. Media solidified with varying concentrations of a variety of gelling agents (agar, bacto agar, gelrite and phytagel) were tested for their impact on the frequency of callus induction, shoot regeneration and rooting. The results indicated gellan gum (gelrite and phytagel) was superior to agar products (agar and bacto agar) for callus induction. By contrast, no significant differences were found between different gelling agents for shoot regeneration. Gellan gum and media solidified with bacto agar were found to lead to significantly higher root regeneration than agar. The Sakha104 cultivar showed better responses than Giza 178 for callus induction and similar performance to the Giza 178 cultivar for root regeneration irrespective of the gelling agent. This work provides insights into the impact of different gelling agents on the morphogenetic response of two rice cultivars and can be used to help maximize the frequency of rice regeneration.     

RETRACTED ARTICLE: Changes in parameters of biochemical and oxidative stress in university students during and after examinations

The study aimed to evaluate the parameters of lipid peroxidation and antioxidant protection, biochemical parameters, and cortisol and adrenaline content in the blood of students depending on the effect of exam stress. A total of 135 healthy students (72 female (53.3%) and 63 male (46.7%)) aged from 19 to 21 years (mean age 20.16 ± 0.42 years) of the experimental group underwent detailed medical screening and examination before the inclusion in the study. The control group consisted of 30 healthy students (17 female (56.7%) and 13 male (43.3%)) of corresponding age (mean age 20.23 ± 0.54 years), whose medical examination was performed during breaks in the absence of any stress factors. The blood parameters of the experimental group were investigated 1 h before, 1 h after, and 24 h after the exam. The cortisol content in the blood of experimental group students significantly increased 1.37 times (p < 0.05) an hour before the exam and 1.32 times (p < 0.05) an hour after; adrenalin content in blood increased 1.76 times (p < 0.05) and 1.49 times (p < 0.05), respectively. Compared to the control group, intensification of lipid peroxidation processes with a 1.51-fold (p < 0.05) increase in erythrocyte malonic aldehyde content in blood 1 h before and 1.42-fold (p < 0.05) increase an hour after the exam was observed in students due to the effect of exam stress.. Changes in hormonal homeostasis, activation of lipoperoxidation processes with the development of oxidative stress, and the disintegration of antioxidant protection factors are typical for academic stress in students.     

Genetic variation and migration pathways of maritime pine (Pinus pinaster Ait) in the Iberian peninsula

The genetic variability and migration pathways of Pinus pinaster after glaciation in the Iberian peninsula was studied by means of 18 loci from 12 natural populations of the species. The analysis showed the existence of three groups of populations with different levels of diversity and patterns of recolonization. The southern Iberian group displays a high level of diversity, with a stepping-stone model of variation. The presence of rare alleles in this group and their position in the phylogenetic tree suggest the existence of refugia during glaciations in this zone. The eastern Iberian group also has high levels of diversity but is clearly separate from the first group based on their genetic distances. The Atlantic group displays a low level of diversity that could be interpreted as a rapid recolonization of the entire area by the Eastern group that has not yet developed to a divergence in this area. The southern Iberian range is indicated to be the dispersal centre of the species after the last glaciation. Received: 15 February 1999 / Accepted: 30 April 1999     

Convenient method of threonine, methionine and their related amino compounds by high-performance liquid chromatography and its application to rumen fluid

A high-performance liquid chromatographic procedure for the quantitative determination of cysteine (Cys), homocysteine (Hcys), methionine sulfoxide (MSO), methionine sulfone (MSO₂), homoserine (Hser), glycine (Gly), threonine (Thr), 2-aminobutyric acid (2AB), methionine (Met), cystathionine (Cysta) and its application to rumen fluid are described. The samples containing Thr, Met and other related amino compounds were derivatized with 9-fluorenylmethyl chloroformate. The separation of compounds was accomplished with a methanol gradient in 25 mM sodium citrate buffer (obtaining pH 6.40 and 3.80 by addition of 25 mM citric acid). All derivatized compounds were separated on a Mightysil RP-18 GP (150×4.6 mm I.D., 5 μm particle size) column. All analytes were detected at 265 nm with UV detection. The limits of detection (μM) (S/N ratio, 3:1) and quantification (μM) (S/N ratio, 10:1) of Cys, Hcys, MSO, MSO₂, Hser, Gly, Thr, 2AB, Met and Cysta were 0.50 and 1.68; 1.76 and 5.85; 0.85 and 2.88; 0.92 and 3.09; 1.04 and 3.52; 0.76 and 2.52; 0.65 and 2.18; 0.39 and 1.36; 0.31 and 1.03; 0.17 and 0.58, respectively. The recoveries of all compounds in rumen fluid were 97.93–102.3% in the within-day study and 94.52–98.69% on different day (6 days) studies. The average contents (μM) of Cys, Gly, Thr, 2AB, Met and Cysta were 1.72, 45.6, 20.0, 4.3, 2.11 and 3.42 before morning feeding. The concentration of Thr, 2AB and Cysta in rumen fluid tended to increase with time after feeding whereas Met showed the opposite tendency.     

Central Exendin‐4 Infusion Reduces Body Weight without Altering Plasma Leptin in (fa/fa) Zucker Rats

Objective: To investigate whether chronic administration of the long‐acting glucagon‐like peptide‐1 receptor agonist exendin‐4 can elicit sustained reductions in food intake and body weight and whether its actions require an intact leptin system. Research Methods and Procedures: Male lean and obese Zucker (fa/fa) rats were infused intracerebroventricularly with exendin‐4 using osmotic minipumps for 8 days. Results: Exendin‐4 reduced body weight in both lean and obese Zucker rats, maximum suppression being reached on Day 5 in obese (8%) and Day 7 in lean (16%) rats. However, epididymal white adipose tissue weight was not reduced, and only in lean rats was there a reduction in plasma leptin concentration. Food intake was maximally suppressed (by 81%) on Day 3 in obese rats but was reduced by only 18% on Day 8. Similarly, in lean rats food intake was maximally reduced (by 93%) on Day 4 of treatment and by 45% on Day 8. Brown adipose tissue temperature was reduced from Days 2 to 4. Plasma corticosterone was elevated by 76% in lean but by only 28% in obese rats. Discussion: Chronic exendin‐4 treatment reduced body weight in both obese and lean Zucker rats by reducing food intake: metabolic rate was apparently suppressed. These effects did not require an intact leptin system. Neither does the absence of an intact leptin system sensitize animals to exendin‐4. Partial tolerance to the anorectic effect of exendin‐4 in lean rats may have been due to elevated plasma corticosterone and depressed plasma leptin levels, but other counter‐regulatory mechanisms seem to play a role in obese Zucker rats.     

Antagonistic relationship of NuA4 with the non-homologous end-joining machinery at DNA damage sites

The NuA4 histone acetyltransferase complex, apart from its known role in gene regulation, has also been directly implicated in the repair of DNA double-strand breaks (DSBs), favoring homologous recombination (HR) in S/G2 during the cell cycle. Here, we investigate the antagonistic relationship of NuA4 with non-homologous end joining (NHEJ) factors. We show that budding yeast Rad9, the 53BP1 ortholog, can inhibit NuA4 acetyltransferase activity when bound to chromatin in vitro. While we previously reported that NuA4 is recruited at DSBs during the S/G2 phase, we can also detect its recruitment in G1 when genes for Rad9 and NHEJ factors Yku80 and Nej1 are mutated. This is accompanied with the binding of single-strand DNA binding protein RPA and Rad52, indicating DNA end resection in G1 as well as recruitment of the HR machinery. This NuA4 recruitment to DSBs in G1 depends on Mre11-Rad50-Xrs2 (MRX) and Lcd1/Ddc2 and is linked to the hyper-resection phenotype of NHEJ mutants. It also implicates NuA4 in the resection-based single-strand annealing (SSA) repair pathway along Rad52. Interestingly, we identified two novel non-histone acetylation targets of NuA4, Nej1 and Yku80. Acetyl-mimicking mutant of Nej1 inhibits repair of DNA breaks by NHEJ, decreases its interaction with other core NHEJ factors such as Yku80 and Lif1 and favors end resection. Altogether, these results establish a strong reciprocal antagonistic regulatory function of NuA4 and NHEJ factors in repair pathway choice and suggests a role of NuA4 in alternative repair mechanisms in situations where some DNA-end resection can occur in G1.